Carotid Ultrasound

What is a carotid ultrasound?

A carotid ultrasound, or carotid duplex, is a painless, safe test that uses sound waves to make images of what your carotid arteries look like on the inside. By using the Doppler ultrasound technique, your healthcare provider can also see how well your blood travels through your two carotid arteries, which take blood to your brain.

When would a carotid ultrasound be needed?

You may need a carotid artery ultrasound when your healthcare provider wants to look for blood clots or plaque (fat and cholesterol deposits) on your carotid artery walls. These plaque deposits can limit ― and eventually block ― the flow of blood to your brain, face and neck. A blocked carotid artery can cause a stroke.

You may need a carotid ultrasound if you:

• Had surgery on a narrowed artery.
• Need a follow-up on a stent in your carotid artery.
• Are getting periodic checks because your artery was narrow during a previous checkup.
• Have a bruit (unusual sound like a whoosh) your provider could hear through a stethoscope against your artery.
• Have high blood pressure or high cholesterol.
• Had a stroke or transient ischemic attack (TIA).
• Are going to have coronary artery bypass surgery.
• Have diabetes.
• Have stroke or heart disease in your family.
• Have a hematoma (collection or pool of blood).

Doppler ultrasound helps your provider look at:

• Blood flow.
• Narrowing or blockage in your artery.
• Malformations you’ve had since birth or tumors.

Who performs a carotid ultrasound?

A healthcare provider called a sonographer or ultrasound technologist performs ultrasound tests, but a radiologist also can perform them.

How does a carotid artery ultrasound work?

A carotid ultrasound does not use radiation. It uses sound waves to make pictures of the inside of your carotid arteries. A computer takes the information from the transducer (the device your provider places on your skin) and uses it to make carotid ultrasound images on a monitor. The sonographer can record videos of the scans or save snapshots of them like photos.

How do I prepare for the test?

You don’t need to do anything to prepare for a carotid ultrasound, but you may want to wear a comfortable shirt that doesn’t cover your neck and isn’t tight. If your shirt comes up too high on your neck, you’ll probably need to change into a hospital gown. Don’t wear a necklace or earrings if they’ll be in the way.

What to expect on the date of the test

You’ll go to your healthcare provider’s office or a healthcare facility for the test. You can expect the test to take 30 to 45 minutes.

What to expect during a carotid ultrasound

Your healthcare provider will put some clear gel on the sides of your neck. (You have one carotid artery on each side of your neck.) This gel might feel warm on your skin, but the gel makes it easier for sound waves to travel between your arteries and the transducer your provider uses.

For quality images during the test, it’s best not to move around.

While you’re lying on your back, your provider will press the transducer (smaller than a handheld price scanner at a store) against the skin on the sides of your neck. The sound waves coming out of and back into the transducer after hitting your arteries along the way will tell the computer what the image looks like. Your provider will keep moving the transducer over your skin until they have all the images they need.

You won’t hear the sound waves unless it’s a Doppler ultrasound. In that case, you may hear swishing sounds that change pitch.

What to expect after a carotid artery ultrasound

Your healthcare provider will give you a towel to wipe the gel off of your neck. Then you can get dressed (if you put on a hospital gown) and go home if you’re not getting your results right away. You can go back to your normal activities.

What are the risks of a carotid ultrasound?

This procedure has no risks. You may feel pressure ― but not pain ― when the transducer pushes on your neck.

What type of results do you get and what do the results mean?

Your healthcare provider will get a result that tells whether your arteries are blocked, and how much. This will be a percentage out of 100.

If you get a normal result, your carotid arteries aren’t narrowed or blocked.

If your results aren’t normal, you may have atherosclerosis, a blood clot or some other problem that makes your artery too narrow and puts you at risk for a stroke.

If you have plaque buildup in one or both of your carotid arteries but the blockage is less than 50% (with stroke or TIA symptoms) or 60% (without stroke or TIA symptoms), your provider may tell you to improve your diet, exercise more and stop using tobacco products.

Also, your provider may prescribe medicine to:

• Dissolve blood clots (thrombolytics).
• Prevent blood clots (aspirin or clopidogrel).
• Lower your cholesterol level (statins).
• Bring down your blood pressure (antihypertensives).

If the buildup is more severe (at least 50% with stroke or TIA symptoms or 60% without stroke or TIA symptoms), they may recommend a carotid endarterectomy to remove the plaque. They can use the carotid artery ultrasound results to plan this procedure because it will tell them where the blockage is located. Another treatment for severe blockage, angioplasty, pushes plaque deposits against artery walls to make more room for blood to get through. A stent can hold the artery open after angioplasty.

A carotid ultrasound is generally accurate, but there can be times when it looks like there’s a blockage, but there isn’t one. The experience level of sonographers can vary, and ultrasounds do better at picking up severe problems than milder ones. Your provider may want you to have more imaging tests, such as cerebral, CT or magnetic resonance angiography. One reason you may need these other types of imaging is because of bone that blocks the ultrasound’s view of part of your carotid artery. The ultrasound can’t “see” through the bone.

Stroke risk factors

Other stroke risk factors you have may influence your provider’s decisions about which treatment to recommend for you. You may be at a higher risk of stroke if you have:

• High blood pressure.
• High cholesterol.
• Diabetes.
• Peripheral artery disease (PAD).
• Atrial fibrillation.
• Sickle cell disease.
• Obesity.
• Heart disease.

Using tobacco products, eating a high-fat, high-salt diet and being inactive also increase your risk of a stroke.

When should I know the results of the test?

Sometimes, a radiologist (a healthcare provider who’s an expert at interpreting medical images) will talk with you right away. Other times, the radiologist may send the carotid ultrasound results to your provider, who shares them with you in a couple of days.

When should I call my doctor?

If it’s been a few days since your carotid ultrasound and you don’t have results yet, check with your healthcare provider. Once you have your results, contact your provider if you have questions about your recommended treatment.

A note from Cleveland Clinic

A carotid ultrasound is an easy way to find out if you have narrowing or blocked areas in your carotid arteries. There’s no pain involved, and the test doesn’t take long. If your healthcare provider finds that you have some blockage, you may need to make some changes to your lifestyle. Even if some type of procedure is right for you, you can lower your stroke risk even more with better health habits. Before you know it, you won’t even need to think about healthy changes because they’ll become automatic.